ABB 07KP93 Motor Protection Relay

The ABB 07KP93 GJR5253200R1161 is a multi-function motor protection relay engineered to safeguard industrial motors from catastrophic failures while integrating seamlessly with modern control systems. At its core, a 64-bit ARM Cortex-A9 processor processes real-time data from CTs (current transformers) connected to each motor phase, executing configurable protection logic tailored to motor type (synchronous/asynchronous).

Key Technical Specifications

• Model Number: ABB 07KP93 GJR5253200R1161
• Manufacturer: ABB Power Grids Division
• Protection Functions: Thermal overload (class 5-30), phase unbalance, earth fault (residual), under/overvoltage, locked rotor protection
• Accuracy Class: 0.5S (current measurement), 1.0 (protection elements)
• CPU Architecture: 64-bit ARM Cortex-A9, 1GHz clock speed
• Communication Ports: 2 × 10/100/1000Mbps Ethernet (IEC 61850 GOOSE/MMS), 1 × RS485 (Modbus RTU)
• Power Supply: 110/220V AC/DC ±15% (switch-selectable), 25W max power consumption
• Operating Temperature: -40°C to +70°C (-40°F to +158°F)
• Isolation Rating: 2kV AC (current inputs to control circuit); 1kV AC (communication ports)
• Certifications: IEC 61508 (SIL 2), IEC 60255, CE, UL 508, RoHS 2.0, ATEX Zone 2
• CT Compatibility: 50:5 to 2000:5 (software-configurable, no external transformers)
• Inputs/Outputs: 6 × analog current inputs (3CT), 16 × digital inputs, 8 × configurable relay outputs (NO/NC)
• Fault Record Capacity: 80 fault records with pre/post-fault waveforms (1s pre/3s post)

Field Application & Problem Solved

In industrial motor control—refinery pump stations, power plant cooling fans, chemical reactor agitators—motor failures cost millions annually, and generic relays fail to provide comprehensive protection or safety compliance. A Texas refinery lost $90k in a 3-hour outage when a generic relay failed to detect a locked rotor on a 500HP pump motor, burning out the windings. Legacy relays also lack modern connectivity: an Ohio chemical plant spent $35k on protocol gateways to integrate old motor relays with their IEC 61850 SCADA system, leading to 2 hours of monthly downtime from communication lags.

You’ll find this relay in motor control centers across critical systems: 100-1000HP pump motors in Louisiana petrochemical plants, boiler feedwater fans in Pennsylvania coal plants, and mixer motors in Minnesota pharmaceutical facilities. Its core value is comprehensive motor protection + SIL 2 safety compliance + native modern communication. The thermal overload and locked rotor protection cut the Texas refinery’s motor failure rate by 85%, with zero catastrophic burnouts in 4 years. At the Ohio plant, built-in IEC 61850 support replaced three gateways, eliminating communication delays and saving $28k annually.

For an Alaskan mining facility, the -40°C low-temperature rating proved critical—generic relays failed in winter cold, but the 07KP93 operated reliably for 3 years. Its SIL 2 certification also ensured compliance with OSHA safety regulations for a Florida food processing plant’s critical motors, avoiding $190k in non-compliance fines.

Installation & Maintenance Pitfalls

• CT Wiring Polarity: Don’t Reverse Connections: Rookies mix up CT secondary wiring, causing incorrect current measurements and missed faults. A North Carolina power plant’s fan motor burned out because reversed CT polarity made the relay miss a 150% overload. Follow ABB’s dot notation on CTs and relay terminals—use a phase rotation tester to verify current flow direction before commissioning.
• Protection Curve Selection: Match Motor Type: Using a standard inverse curve for high-inertia motors (e.g., centrifugal compressors) causes nuisance overload trips. A Michigan factory’s compressor motor tripped weekly until we reconfigured the 07KP93 to use IEC 60255-3 Class 20 curve (optimized for long starting times). Cross-reference the motor’s nameplate (locked rotor current, thermal class) with ABB’s application guide to select the correct curve.
• GOOSE Alarm Mapping: Validate Real-Time Alerts: Incorrect IEC 61850 GOOSE configuration delays motor fault alerts to the DCS. A Texas refinery’s pump motor overheated for 2 minutes before the DCS received the alarm, causing minor winding damage. Use ABB’s PCM600 software to map critical alerts (overload, phase unbalance, earth fault) to DCS tags, and test with a GOOSE sniffer to confirm <10ms transmission.
• Annual Testing: Don’t Skip Calibration: Uncalibrated relays drift in protection settings, increasing motor risk. A Minnesota paper mill’s 07KP93 failed to detect a 120% overload because it hadn’t been tested in 2 years. Use ABB’s 1SVR730700R0000 test kit to verify current measurement accuracy and overload pickup settings annually—compare results to the motor’s nameplate data.

The relay’s thermal overload element uses a dynamic model to simulate motor winding temperature, accounting for start-up inrush currents and cyclic loading—avoiding nuisance trips common with generic bimetallic relays. Phase unbalance protection detects current differences >15% (configurable) and trips the motor to prevent single-phasing damage, while earth fault protection monitors residual current to detect ground faults before they escalate.

Native IEC 61850 communication eliminates the need for external gateways, enabling real-time data transfer (motor current, temperature, fault type) to SCADA/DCS systems. GOOSE (Generic Object Oriented Substation Event) supports fast inter-relay communication for coordinated protection schemes (e.g., motor feeder and upstream breaker).

Ruggedization features include a conformal-coated PCB and wide operating temperature range (-40°C to +70°C), ideal for unconditioned motor control centers and extreme climates. Unlike generic relays, it’s factory-calibrated for wide CT ratio compatibility, eliminating the need for external matching transformers. Its SIL 2 certification ensures compliance with safety standards for critical motor applications, making it a reliable backbone for motor protection in environments where downtime costs $10k+/minute.